隧道地质预报全空间瞬变电磁反演方法及评价体系研究

Current, one of major difficult problems in tunnel geological prediction is the groundwater detection in front of the tunnel, faults, lithology change and other problems in tunnel geological prediction has better solution. Therefore, this study aimed at the problem of water detection in front of the tunnel, considered the tunnel whole space transient electromagnetic effect, its inversion methods and evaluation system is put on research, it mainly solves the following key problems:.(1) To determine the main factors of effecting tunnel whole space transient electromagnetic effect and its weight order, find out the relations between whole and half space transient electromagnetic effect and its law..(2) Leading in the formulas of whole space transient electromagnetic effect, the inversion formulas on one dimensional half space transient electromagnetism are modified, and the inversion numerical models for 3D transient electromagnetism are established,the uncertain prolems of geological body in front of tunnel are solved by programming..(3) Used a variety of methods of mathematical analysis, with the original an result data as samples, the intelligent database with learning and infering function is set up, and the multiple means of intelligent inversion and its evaluation system has been formed..This research will improve the accuracy rating for tunnel advanced predicting groundwater, which has provided the technical supports for the safety of tunnel construction.

当前，隧道地质预报的主要难点之一是隧道前方地下水的探测问题，断层、岩性变化等问题在隧道地质预报中已经得到较好地解决。为此，本研究针对隧道超前探水问题，考虑隧道全空间瞬变电磁效应的影响，对其反演方法及评价体系开展研究，主要解决以下关键问题：.(1) 确定影响隧道全空间瞬变电磁效应的主要因素和权重排序，找出全空间与半空间瞬变电磁效应间的关系及其规律。.(2) 引入全空间瞬变电磁效应关系式，对一维半空间瞬变电磁反演式进行修改，建立三维全空间瞬变电磁反演数值模型，编程求解隧道超前地质体的多解不确定问题。.(3) 应用多种数学分析方法，以原始和结果数据为样本，建立具有学习和推测功能的智能数据库，形成多手段智能反演及其评价体系。.本研究提高了隧道超前探水的准确率，为隧道施工安全提供了技术保障。

随着大量隧道工程的修建，能否准确的探测及辨别开挖前方的不良富水地质体将极大的影响隧道工程的施工安全及施工速度。瞬变电磁法从原理上对地下水敏感，但已有的瞬变电磁法探水技术及设备对隧道工程的适用性仍然有待提高。本研究通过数值模拟计算及物理相似模型试验确定了隧道开挖过程中各影响因素对瞬变电磁法探测技术的影响。通过大量的理论分析及模拟计算确定了在三维全空间场中瞬变电磁效应与半空间中瞬变电磁效应的联系与区别，并根据这种联系与区别进一步展开隧道三维全空间瞬变电磁探水反演的研究，找出了全空间三维瞬变电磁反演与半空间瞬变电磁反演的联系与区别。根据大量的模拟计算结果与现场实测数据建立了隧道瞬变电磁探水的数据库系统，并根据此数据库建立了数据库专家反演系统；同时研发了瞬变电磁法神经网络专家系统及瞬变电磁法LSSVM专家系统，该系统可以通过自主学习随着使用不断的提高其反演计算的精确度。